#include <stdio.h>

int main(void) {
    char a, b, c;
    scanf("%c%c%c", &a, &b, &c);
    if (a == b && b == c && a == c) {
        printf("No");
    } else if (a == b || b == c || a == c) {
        printf("Yes");
    } else {
        printf("No");
    }
    return 0;
}
